Grade 8 hex cap screws are manufactured from medium carbon steel quenched and tempered to a high degree, these screws meet ASTM A-354 BD, SAE J-429 Grade 8, and SAE chemistry and mechanical specifications. Grade 8 hex head cap screws have greater tensile strength than Grade 5 and used in high stress applications. Stocked in diameters from 1/4" to 1" and lengths up to 14". Head markings for grade 8 bolts is most commonly 6 lines in some arrangement.